pub struct NonZeroU8(_);
Expand description
An integer that is known not to equal zero.
This enables some memory layout optimization.
For example, Option<NonZeroU8>
is the same size as u8
:
use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroU8>>(), size_of::<u8>());
RunImplementations§
source§impl NonZeroU8
impl NonZeroU8
const: 1.28.0 · sourcepub const unsafe fn new_unchecked(n: u8) -> NonZeroU8
pub const unsafe fn new_unchecked(n: u8) -> NonZeroU8
Creates a non-zero without checking whether the value is non-zero. This results in undefined behaviour if the value is zero.
Safety
The value must not be zero.
source§impl NonZeroU8
impl NonZeroU8
1.53.0 (const: 1.53.0) · sourcepub const fn leading_zeros(self) -> u32
pub const fn leading_zeros(self) -> u32
Returns the number of leading zeros in the binary representation of self
.
On many architectures, this function can perform better than leading_zeros()
on the underlying integer type, as special handling of zero can be avoided.
Examples
Basic usage:
let n = std::num::NonZeroU8::new(u8::MAX).unwrap();
assert_eq!(n.leading_zeros(), 0);
Run1.53.0 (const: 1.53.0) · sourcepub const fn trailing_zeros(self) -> u32
pub const fn trailing_zeros(self) -> u32
Returns the number of trailing zeros in the binary representation
of self
.
On many architectures, this function can perform better than trailing_zeros()
on the underlying integer type, as special handling of zero can be avoided.
Examples
Basic usage:
let n = std::num::NonZeroU8::new(0b0101000).unwrap();
assert_eq!(n.trailing_zeros(), 3);
Runsource§impl NonZeroU8
impl NonZeroU8
1.64.0 (const: 1.64.0) · sourcepub const fn checked_add(self, other: u8) -> Option<NonZeroU8>
pub const fn checked_add(self, other: u8) -> Option<NonZeroU8>
Adds an unsigned integer to a non-zero value.
Checks for overflow and returns None
on overflow.
As a consequence, the result cannot wrap to zero.
Examples
let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(Some(two), one.checked_add(1));
assert_eq!(None, max.checked_add(1));
Run1.64.0 (const: 1.64.0) · sourcepub const fn saturating_add(self, other: u8) -> NonZeroU8
pub const fn saturating_add(self, other: u8) -> NonZeroU8
sourcepub const unsafe fn unchecked_add(self, other: u8) -> NonZeroU8
🔬This is a nightly-only experimental API. (nonzero_ops
#84186)
pub const unsafe fn unchecked_add(self, other: u8) -> NonZeroU8
nonzero_ops
#84186)Adds an unsigned integer to a non-zero value,
assuming overflow cannot occur.
Overflow is unchecked, and it is undefined behaviour to overflow
even if the result would wrap to a non-zero value.
The behaviour is undefined as soon as
self + rhs > u8::MAX
.
Examples
#![feature(nonzero_ops)]
let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
assert_eq!(two, unsafe { one.unchecked_add(1) });
Run1.64.0 (const: 1.64.0) · sourcepub const fn checked_next_power_of_two(self) -> Option<NonZeroU8>
pub const fn checked_next_power_of_two(self) -> Option<NonZeroU8>
Returns the smallest power of two greater than or equal to n.
Checks for overflow and returns None
if the next power of two is greater than the type’s maximum value.
As a consequence, the result cannot wrap to zero.
Examples
let two = NonZeroU8::new(2)?;
let three = NonZeroU8::new(3)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(Some(two), two.checked_next_power_of_two() );
assert_eq!(Some(four), three.checked_next_power_of_two() );
assert_eq!(None, max.checked_next_power_of_two() );
Run1.67.0 (const: 1.67.0) · sourcepub const fn ilog2(self) -> u32
pub const fn ilog2(self) -> u32
Returns the base 2 logarithm of the number, rounded down.
This is the same operation as
u8::ilog2
,
except that it has no failure cases to worry about
since this value can never be zero.
Examples
assert_eq!(NonZeroU8::new(7).unwrap().ilog2(), 2);
assert_eq!(NonZeroU8::new(8).unwrap().ilog2(), 3);
assert_eq!(NonZeroU8::new(9).unwrap().ilog2(), 3);
Run1.67.0 (const: 1.67.0) · sourcepub const fn ilog10(self) -> u32
pub const fn ilog10(self) -> u32
Returns the base 10 logarithm of the number, rounded down.
This is the same operation as
u8::ilog10
,
except that it has no failure cases to worry about
since this value can never be zero.
Examples
assert_eq!(NonZeroU8::new(99).unwrap().ilog10(), 1);
assert_eq!(NonZeroU8::new(100).unwrap().ilog10(), 2);
assert_eq!(NonZeroU8::new(101).unwrap().ilog10(), 2);
Runsource§impl NonZeroU8
impl NonZeroU8
1.64.0 (const: 1.64.0) · sourcepub const fn checked_mul(self, other: NonZeroU8) -> Option<NonZeroU8>
pub const fn checked_mul(self, other: NonZeroU8) -> Option<NonZeroU8>
Multiplies two non-zero integers together.
Checks for overflow and returns None
on overflow.
As a consequence, the result cannot wrap to zero.
Examples
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(Some(four), two.checked_mul(two));
assert_eq!(None, max.checked_mul(two));
Run1.64.0 (const: 1.64.0) · sourcepub const fn saturating_mul(self, other: NonZeroU8) -> NonZeroU8
pub const fn saturating_mul(self, other: NonZeroU8) -> NonZeroU8
sourcepub const unsafe fn unchecked_mul(self, other: NonZeroU8) -> NonZeroU8
🔬This is a nightly-only experimental API. (nonzero_ops
#84186)
pub const unsafe fn unchecked_mul(self, other: NonZeroU8) -> NonZeroU8
nonzero_ops
#84186)Multiplies two non-zero integers together,
assuming overflow cannot occur.
Overflow is unchecked, and it is undefined behaviour to overflow
even if the result would wrap to a non-zero value.
The behaviour is undefined as soon as
self * rhs > u8::MAX
.
Examples
#![feature(nonzero_ops)]
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
assert_eq!(four, unsafe { two.unchecked_mul(two) });
Run1.64.0 (const: 1.64.0) · sourcepub const fn checked_pow(self, other: u32) -> Option<NonZeroU8>
pub const fn checked_pow(self, other: u32) -> Option<NonZeroU8>
Raises non-zero value to an integer power.
Checks for overflow and returns None
on overflow.
As a consequence, the result cannot wrap to zero.
Examples
let three = NonZeroU8::new(3)?;
let twenty_seven = NonZeroU8::new(27)?;
let half_max = NonZeroU8::new(u8::MAX / 2)?;
assert_eq!(Some(twenty_seven), three.checked_pow(3));
assert_eq!(None, half_max.checked_pow(3));
Run1.64.0 (const: 1.64.0) · sourcepub const fn saturating_pow(self, other: u32) -> NonZeroU8
pub const fn saturating_pow(self, other: u32) -> NonZeroU8
source§impl NonZeroU8
impl NonZeroU8
1.59.0 (const: 1.59.0) · sourcepub const fn is_power_of_two(self) -> bool
pub const fn is_power_of_two(self) -> bool
Returns true
if and only if self == (1 << k)
for some k
.
On many architectures, this function can perform better than is_power_of_two()
on the underlying integer type, as special handling of zero can be avoided.
Examples
Basic usage:
let eight = std::num::NonZeroU8::new(8).unwrap();
assert!(eight.is_power_of_two());
let ten = std::num::NonZeroU8::new(10).unwrap();
assert!(!ten.is_power_of_two());
RunTrait Implementations§
source§impl Ord for NonZeroU8
impl Ord for NonZeroU8
source§impl PartialEq<NonZeroU8> for NonZeroU8
impl PartialEq<NonZeroU8> for NonZeroU8
source§impl PartialOrd<NonZeroU8> for NonZeroU8
impl PartialOrd<NonZeroU8> for NonZeroU8
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read more1.49.0 · source§impl TryFrom<NonZeroI128> for NonZeroU8
impl TryFrom<NonZeroI128> for NonZeroU8
source§fn try_from(
value: NonZeroI128
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI128>>::Error>
fn try_from( value: NonZeroI128 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI128>>::Error>
Attempts to convert NonZeroI128
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroI16> for NonZeroU8
impl TryFrom<NonZeroI16> for NonZeroU8
source§fn try_from(
value: NonZeroI16
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI16>>::Error>
fn try_from( value: NonZeroI16 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI16>>::Error>
Attempts to convert NonZeroI16
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroI32> for NonZeroU8
impl TryFrom<NonZeroI32> for NonZeroU8
source§fn try_from(
value: NonZeroI32
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI32>>::Error>
fn try_from( value: NonZeroI32 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI32>>::Error>
Attempts to convert NonZeroI32
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroI64> for NonZeroU8
impl TryFrom<NonZeroI64> for NonZeroU8
source§fn try_from(
value: NonZeroI64
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI64>>::Error>
fn try_from( value: NonZeroI64 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI64>>::Error>
Attempts to convert NonZeroI64
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroIsize> for NonZeroU8
impl TryFrom<NonZeroIsize> for NonZeroU8
source§fn try_from(
value: NonZeroIsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroIsize>>::Error>
fn try_from( value: NonZeroIsize ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroIsize>>::Error>
Attempts to convert NonZeroIsize
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroU128> for NonZeroU8
impl TryFrom<NonZeroU128> for NonZeroU8
source§fn try_from(
value: NonZeroU128
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU128>>::Error>
fn try_from( value: NonZeroU128 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU128>>::Error>
Attempts to convert NonZeroU128
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroU16> for NonZeroU8
impl TryFrom<NonZeroU16> for NonZeroU8
source§fn try_from(
value: NonZeroU16
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU16>>::Error>
fn try_from( value: NonZeroU16 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU16>>::Error>
Attempts to convert NonZeroU16
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroU32> for NonZeroU8
impl TryFrom<NonZeroU32> for NonZeroU8
source§fn try_from(
value: NonZeroU32
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU32>>::Error>
fn try_from( value: NonZeroU32 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU32>>::Error>
Attempts to convert NonZeroU32
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroU64> for NonZeroU8
impl TryFrom<NonZeroU64> for NonZeroU8
source§fn try_from(
value: NonZeroU64
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU64>>::Error>
fn try_from( value: NonZeroU64 ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU64>>::Error>
Attempts to convert NonZeroU64
to NonZeroU8
.
§type Error = TryFromIntError
type Error = TryFromIntError
1.49.0 · source§impl TryFrom<NonZeroUsize> for NonZeroU8
impl TryFrom<NonZeroUsize> for NonZeroU8
source§fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroUsize>>::Error>
fn try_from( value: NonZeroUsize ) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroUsize>>::Error>
Attempts to convert NonZeroUsize
to NonZeroU8
.